_______ necessary for us _______ our environment clean and tidy.
A. This is; keep
B. That’s; to keep
C. It’s; to keep
D. It’s; keep
She was afraid of __________SARS because it was dangerous.
A. catch B. catches
C. caught D. catching
-----Who taught _________Japanese?
----I learned it by ______________.
A. you, myself
B. your, I
C. yourself , me
D. yourself, myself
Humans can’t live _______air.
A. without B. with
C. in D. for
---Oh, you have a headache and a cough. _______have you been like this?
---Three days.
A. How long B. How soon
C. How often D. How many
I prefer_____ to ______.
A. sing, dance
B. singing, dancing
C. singing, dance
D. sing, dancing
